Math
Dimensional Weight (DIM Weight) vs. Actual Weight billable shipping formula
Compare dimensional and scale weight using a supplied divisor and an explicit whole-pound rounding assumption.
Compare two weight bases under a stated shipping rule
This example assumes dimensions in inches already measured and rounded under the selected service rules, scale weight in pounds, a divisor of 139 cubic inches per pound, and rounding each weight upward to whole pounds. These are illustrative inputs, not a universal carrier tariff. Confirm dimension rounding, divisor, minimum weight and rounding increment for your actual service and contract.
For the supplied 24 by 18 by 12 dimensions, dimensional weight is 38 pounds and rounded scale weight is 20 pounds. The 18-pound difference is an increase in the weight basis, not a dollar surcharge. Prices, additional handling, oversize and other charges are not calculated. A divisor of 166 is a separate hypothetical comparison.
| Carton Profile (Divisor = 139 in^3/lb) | Scale Weight (Rounded Up) | DIM Weight ROUNDUP(L*W*H/139, 0) | Billable Weight |
|---|---|---|---|
| Bulky Pillow Box (24×18×12 in, 19.4 lb) | 20 lb | ROUNDUP(5184 / 139, 0) = 38 lb | 38 lb (DIM Wins!) |
| Dense Steel Parts (24×18×12 in, 44.2 lb) | 45 lb | 38 lb | 45 lb (Scale Wins!) |
| Negotiated Divisor 166 (24×18×12 in, 19.4 lb) | 20 lb | ROUNDUP(5184 / 166, 0) = 32 lb | 32 lb (Saves 6 lb!) |
Calculate carrier Billable Weight (MAX of Scale vs. DIM)
A2:C2 are the prepared dimensions in inches, D2 is scale weight in pounds, and E2 is the divisor in cubic inches per pound. All must be positive numeric values. A metric service may use different units and rounding increments; do not merely relabel this sheet.
=IF(OR(COUNT(A2:E2)<>5,MIN(A2:E2)<=0),"Invalid inputs",MAX(ROUNDUP(D2, 0), ROUNDUP((A2 * B2 * C2) / E2, 0)))Increase in modeled billable pounds due to volume
Returns the difference between the modeled billable weight and rounded scale weight. It does not calculate a fee.
=IF(OR(COUNT(A2:E2)<>5,MIN(A2:E2)<=0),"Invalid inputs",MAX(0, ROUNDUP((A2 * B2 * C2) / E2, 0) - ROUNDUP(D2, 0)))Try the example
Use the original values or change them to test your understanding.